Formic acid is responsible for the sting of an ant bite. An aqueous solution of formic acid has a molality of 11.19m and a solution density of 1.0842 g/mL. What are the molarity, mole fraction and % by mass of the solute in this solution?

Answer: 8.008M, 34%, X=.1677
I started doing this:
11.19 mol HCOOH/(.001 g H2O) * (18g H2O/1mol H2O)

I'm already stuck and I don't even know if I am doing this right so far. Can anyone show how to get these answers, please?? D:

Question

Formic acid is responsible for the sting of an ant bite. An aqueous solution of formic acid has a molality of 11.19m and a solution density of 1.0842 g/mL. What are the molarity, mole fraction and % by mass of the solute in this solution? 

Answer: 8.008M, 34%, X=.1677
I started doing this:
11.19 mol HCOOH/(.001 g H2O) * (18g H2O/1mol H2O)

I'm already stuck and I don't even know if I am doing this right so far. Can anyone show how to get these answers, please?? D:

anonymous · Answer

Molality = 11.19 (given in the question)
u might be knowing the formula of molality.
write that formula 
and then write the formula of molarity.

what's the difference between these two formulas?

anonymous · Answer

molality is moles of solute/kg solvent
molarity is moles/liters

anonymous · Answer

yes... good.

now you see that if somehow, you could change the kilograms in the molality formula to litres, you will end up with molarity. of the solution.

and you know, density = mass / volume
so, mass (kg) = density * volume( in L)

can yu do it now?

anonymous · Answer

so I'm converting the kg of H2O (the solvent) to liters?? I'm sure the solution is simple, but I've been trying this problem for a while and OS is kind of my last resort...which is why I asked this problem in the first place :/